This invention relates to a universal data select unit for selecting data from a number of busses of different format for analysis by a test computer and at a test bench.
The prior art includes U.S. Pat. No. 4,217,580 to Lowenschuss which discloses an electronic countermeasure system wherein a signal processing circuit is included to enable only a predetermined number of digital words associated with one of a plurality of radio frequency energy sources to pass to a general purpose computer. U.S. Pat. No. 3,975,730 to Maeda et al discloses radar data selection equipment which includes a gate disposal between a target data detector and a computer capable of inhibiting the output of specific signals among the data from the radar.
Many present day aircraft radars use several serial duplex busses for communication with the various radar and system units. Being major information points, these busses are always instrumented (recorded) during flight test and are normally monitored if possible during bench test.
The normal transfer on these busses starts with a command word which may or may not totally define the information to follow. The information following the command word depends on the buss, it can be a single data word, a fixed number of data words, or a variable number of words depending on the particular data being transferred.
During reduction of the flight test data, it is normally desired to only process a limited number of the possible parameters from the various busses during a single run. This occurs due to the particular type of processing being performed and a limited hardcopy capability. Even though the reduction computer is only interested in some of the parameters, it must accept all and search the information for the desired ones increasing the processing time. This requires the flight data to be played back at a slower rate increasing the reduction time. As many runs are normally made from a single flight, this increase in time becomes very significant.
During bench test, the same problem is encountered, but the controlling bench computer does not normally have the available processing time to handle this data as it must be done in real time. Normally this is solved by adding monitoring circuitry which feeds some type of output device for display. This circuitry requires indentical hardware for each signal it desires to monitor, plus only provides a very limited capability as it can normally only monitor the single word or fixed length transfers. This also fixes the number of signals which can be monitored at any one time, plus only allows one type of display which may not be the best display for the particular data item.